This research project aims to characterize the Sleep Health and Sleep Health knowledge of Mexican-American Hispanics and how this affects their health and health disparities. Little is known about the Sleep Health in Hispanics. In a previous report, the prevalence of snoring in a Hispanic-American population was high and was associated with excessive daytime somnolence and cardiovascular disease. It has also been suggested that acculturation to the American lifestyle may actually be detrimental to Hispanics, in terms of adopting positive health behaviors, including healthy sleep behaviors. This project hypothesizes that the Sleep Health and Sleep Health knowledge are lower among Mexican-American Hispanics as compared to non-Hispanic Whites, and this is associated with poorer quality of life and overall health. We also hypothesize that acculturation to the American lifestyle is associated with the Sleep Health of Mexican-American Hispanics. To test these hypotheses we plan to undertake an extensive telephone survey on sleep health, knowledge, and sleep health habits among 2,000 randomly selected adult subjects who identify themselves as Mexican-American in the San Diego California area and compare them to 2,000 individuals who identify themselves as non-Hispanic White. We also plan to obtain prevalence data on sleep disordered breathing, restless leg syndrome and insomnia, and parasomnias by performing overnight sleep studies in a random sample of 500 subjects per group. If our hypotheses are correct, interventions to improve health and health disparities among U.S. Mexican-American Hispanics should include intensive focus on Sleep Health and Sleep Health knowledge deficits. Key Words: Sleep disorders; Minority health; Epidemiology.